• Biomolecules & Therapeutics
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• v.23 no.1
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• pp.31-38
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• 2015

Histone acetylation plays a critical role in the regulation of transcription by altering the structure of chromatin, and it may influence the resistance of some tumor cells to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) by regulating the gene expression of components of the TRAIL signaling pathway. In this study, we investigated the effects and molecular mechanisms of trichostatin A (TSA), a histone deacetylase inhibitor, in sensitizing TRAIL-induced apoptosis in Caki human renal carcinoma cells. Our results indicate that nontoxic concentrations of TSA substantially enhance TRAIL-induced apoptosis compared with treatment with either agent alone. Cotreatment with TSA and TRAIL effectively induced cleavage of Bid and loss of mitochondrial membrane potential (MMP), which was associated with the activation of caspases (-3, -8, and -9) and degradation of poly (ADP-ribose) polymerase (PARP), contributing toward the sensitization to TRAIL. Combined treatment with TSA and TRAIL significantly reduced the levels of the cellular Fas-associated death domain (FADD)-like interleukin-$1{\beta}$-converting enzyme (FLICE) inhibitory protein (c-FLIP), whereas those of death receptor (DR) 4, DR5, and FADD remained unchanged. The synergistic effect of TAS and TRAIL was perfectly attenuated in c-$FLIP_L$-overexpressing Caki cells. Taken together, the present study demonstrates that down-regulation of c-FLIP contributes to TSA-facilitated TRAIL-induced apoptosis, amplifying the death receptor, as well as mitochondria-mediated apoptotic signaling pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.2
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• pp.91-97
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• 2010

Epidermal keratinocytes overgrow in response to ultraviolet-B (UVB), which may be associated with skin photoaging and cancer development. Recently, we found that HIF-$1{\alpha}$ controls the keratinocyte cell cycle and thereby contributes to epidermal homeostasis. A further study demonstrated that HIF-$1{\alpha}$ is down-regulated by UVB and that this process is involved in UVB-induce skin hyperplasia. Therefore, we hypothesized that the forced expression of HIF-$1{\alpha}$ in keratinocytes would prevent UVB-induced keratinocyte overgrowth. Among several agents known to induce HIF-$1{\alpha}$, pyrithione-zinc (Py-Zn) overcame the UVB suppression of HIF-$1{\alpha}$ in cultured keratinocytes. Mechanistically, Py-Zn blocked the degradation of HIF-$1{\alpha}$ protein in keratinocytes, while it did not affect the synthesis of HIF-$1{\alpha}$. Moreover, the p21 cell cycle inhibitor was down-regulated after UVB exposure, but was robustly induced by Py-Zn. In mice repeatedly irradiated with UVB, the epidermis became hyperplastic and HIF-$1{\alpha}$ disappeared from nuclei of epidermal keratinocytes. However, a cream containing Py-Zn effectively prevented the skin thickening and up-regulated HIF-$1{\alpha}$ to the normal level. These results suggest that Py-Zn is a potential agent to prevent UVB-induced photoaging and skin cancer development. This work also provides insight into a molecular target for treatment of UVB-induced skin diseases.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.132-137
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• 2014

BACKGROUND/OBJECTIVES: In this study, the apoptogenic activity and mechanisms of cell death induced by hexane extract of aged black garlic (HEABG) were investigated in human leukemic U937 cells. MATERIALS/METHODS: Cytotoxicity was evaluated by MTT (3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide) assay. Apoptosis was detected using 4,6-diamidino-2-phenyllindile (DAPI) staining, agarose gel electrophoresis and flow cytometry. The protein levels were determined by Western blot analysis. Caspase activity was measured using a colorimetric assay. RESULTS: Exposure to HEABG was found to result in a concentration- and time-dependent growth inhibition by induction of apoptosis, which was associated with an up-regulation of death receptor 4 and Fas legend, and an increase in the ratio of Bax/Bcl-2 protein expression. Apoptosis-inducing concentrations of HEABG induced the activation of caspase-9, an initiator caspase of the mitochodrial mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase. HEABG also induced apoptosis via a death receptor mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid, and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. However, pre-treatment of U937 cells with the caspase-3 inhibitor, z-DEVD-fmk, significantly blocked the HEABG-induced apoptosis of these cells, and increased the survival rate of HEABG-treated cells, confirming that HEABG-induced apoptosis is mediated through activation of caspase cascade. CONCLUSIONS: Based on the overall results, we suggest that HEABG reduces leukemic cell growth by inducing caspase-dependent apoptosis through both intrinsic and extrinsic pathways, implying its potential therapeutic value in the treatment of leukemia.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.68-68
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• 2018

In this study, we investigated whether S. baicalensis rhizome ethanol extract (SBRE) has antioxidant capacities against oxidative stress induced cellular damage in the HaCaT keratinocytes. Our results revealed that treatment with SBRE prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased the HaCaT cell viability. SBRE also effectively attenuated $H_2O_2$ induced comet tail formation, and inhibited the $H_2O_2$ induced phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V positive cells. In addition, SBRE exhibited scavenging activity against intracellular ROS generation and restored the mitochondria membrane potential loss induced by $H_2O_2$. Moreover, $H_2O_2$ enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with SBRE. Furthermore, SBRE increased the levels of HO-1 associated with the induction of Nrf2. Therefore, we believed that SBRE may potentially serve as an agent for the treatment and prevention of neurodegenerative diseases caused by oxidative stress.

• Journal of Ginseng Research
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• v.46 no.5
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• pp.700-709
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• 2022

Background: Ginsenoside Rd is a natural compound with promising neuroprotective effects. However, the underlying mechanisms are still not well-understood. In this study, we explored whether ginsenoside Rd exerts protective effects on cerebral endothelial cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment and its potential docking proteins related to the underlying regulations. Method: Commercially available primary human brain microvessel endothelial cells (HBMECs) were used for in vitro OGD/R studies. Cell viability, pyroptosis-associated protein expression and tight junction protein degradation were evaluated. Molecular docking proteins were predicted. Subsequent surface plasmon resonance (SPR) technology was utilized for validation. Flow cytometry was performed to quantify caspase-1 positive and PI positive (caspase-1+/PI+) pyroptotic cells. Results: Ginsenoside Rd treatment attenuated OGD/R-induced damage of blood-brain barrier (BBB) integrity in vitro. It suppressed NLRP3 inflammasome activation (increased expression of NLRP3, cleaved caspase-1, IL-1β and GSDMD-N terminal (NT)) and subsequent cellular pyroptosis (caspase-1+/PI + cells). Ginsenoside Rd interacted with SLC5A1 with a high affinity and reduced OGD/R-induced sodium influx and potassium efflux in HBMECs. Inhibiting SLC5A1 using phlorizin suppressed OGD/R-activated NLRP3 inflammasome and pyroptosis in HBMECs. Conclusion: Ginsenoside Rd protects HBMECs from OGD/R-induced injury partially via binding to SLC5A1, reducing OGD/R-induced sodium influx and potassium efflux, thereby alleviating NLRP3 inflammasome activation and pyroptosis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.796-801
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• 2008

Bone is a dynamic tissue that is regulated by the balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Curcumin isolated from Kang-hwang (Turmeric) is widely used as a foodstuff, cosmetic, and medicine. However, the effect of curcumin isolated from Kang-hwang in osteoclast differentiation remains unknown. In this study, we sought to examine the role of curcumin in osteoclast differentiation. Here we show that curcumin greatly inhibited RANKL-mediated osteoclast differentiation in osteoclast precursors without cytotoxicity. RANKL induced the phosphorylation of p38 and JNK mitogen-activated protein kinase (MAPK) and mediated $I-{\kappa}B$ degradation in bone marrow macrophages (BMMs). However, RANKL-mediated p38 MAPK phosphorylation was inhibited by the addition of curcumin. Curcumin inhibited the mRNA expression of TRAP, c-Fos, and NFATc1 in BMMs treated with RANKL. Furthermore, the protein expression of c-Fos and NFATc1 induced by RANKL was suppressed by curcumin treatment. Taken together, our results suggest that curcumin may have a potential therapeutic role in bone-related diseases such as osteoporosis by inhibiting osteoclast differentiation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.766-770
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• 2008

Bone is a dynamic tissue that is regulated by the balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Curcumin isolated from Kang-hwang (Turmeric) is widely used as a foodstuff, cosmetic, and medicine. However, the effect of curcumin isolated from Kang-hwang in osteoclast differentiation remains unknown. In this study, we sought to examine the role of curcumin in osteoclast differentiation. Here we show that curcumin greatly inhibited RANKL-mediated osteoclast differentiation in osteoclast precursors without cytotoxicity. RANKL induced the phosphorylation of p38 and JNK mitogen-activated protein kinase (MAPK) and mediated $I-{\kappa}B$ degradation in bone marrow macrophages (BMMs). However, RANKL-mediated p38 MAPK phosphorylation was inhibited by the addition of curcumin. Curcumin inhibited the mRNA expression of TRAP, c-Fos, and NFATc1 in BMMs treated with RANKL. Furthermore, the protein expression of c-Fos and NFATc1 induced by RANKL was suppressed by curcumin treatment. Taken together, our results suggest that curcumin may have a potential therapeutic role in bone-related diseases such as osteoporosis by inhibiting osteoclast differentiation.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.165-171
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• 2006

Osteoarthritis is thought to be induced by the ageing-related loss of homeostatic balance between degeneration and repair mechanism around cartilage tissue in which inflammatory mediators such as reactive oxygen species, cytokines and prostaglandins are prone to overproduction under undesirable physiological conditions. Phlorotannins are unique polyphenolic compounds bearing dibenzo-1,4-dioxin skeleton which are not found in terrestrial plants but found only in some brown algal species such as Ecklonia and Eisenia families. Phlorotanninrich extracts of Ecklonia cava including LAD103 showed significant antioxidant activities such as DPPH radical scavenging, ferric ion reduction, peroxynitrite scavenging, and inhibition of LDL oxidation, indicating their possible antioxidative interference both in onset and downstream consequences of osteoarthritis. LAD103 also showed significant down regulation of $PGE_2$ generation in LPS-treated RAW 246.7 cells, and significant inhibition of human recombinant interleukin-$1{\alpha}$-induced proteoglycan degradation, indicating its beneficial involvement in pathophysiological consequences of osteoarthritis, the mechanism of which needs further investigation. Since LAD103 showed strong therapeutic potentials in arthritic treatment through several in vitro experiments, it is highly encouraged to perform further mechanistic and efficacy studies.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.346-353
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• 2014

The chlorophyll-related compound pheophorbide a (Pa) was successively purified from an edible red seaweed, Grateloupia elliptica, using silica, octadecyl silica column chromatography and reversed phase-high-performance liquid chromatography, as well as the cell cycle inhibitory and apoptotic effects of Pa being investigated in U87MG glioblastoma cells. The Pa exhibited strong anticancer effects in the absence of direct photo-irradiation against various cancer cell lines, including U87MG, SK-OV-3, and HeLa cells. Among the cancer cells, the strongest anticancer activity of Pa exhibited on U87MG cells with $IC_{50}$ values of 2.8 ${\mu}g/ml$. In addition, Pa specifically had cytostatic activity on glioblastoma cells rather than human umbilical vein endothelial cells. Analysis of the cell cycle distribution showed that Pa induced G0/G1 arrest of U87 MG cells. In addition, arrested cells induced late apoptosis and DNA degradation under dark condition. These results suggest that Pa isolated from G. elliptica is a potential glioblastoma-specific anticancer agent without side effects on normal cells.

• Biomolecules & Therapeutics
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• v.31 no.3
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• pp.306-311
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• 2023

The current study aimed to reveal the potential effect of meclofenamate, a nonsteroidal anti-inflammatory drug, on the gene expression of airway MUC5AC mucin. Human pulmonary mucoepidermoid NCI-H292 cells were pretreated with meclofenamate for 30 min and stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 h. Thereafter, the effect of meclofenamate on the PMA-induced nuclear factor kappa B (NF-kB) signaling pathway was assessed. Meclofenamate inhibited glycoprotein production and mRNA expression of MUC5AC mucins induced by PMA by inhibiting the degradation of inhibitory kappa Bα (IkBα) and NF-kB p65 nuclear translocation. These results suggest meclofenamate suppresses mucin gene expression by regulating NF-kB signaling pathway in human pulmonary epithelial cells.